On the day before the MMORPG known as "Yggdrasil" is shut down, guild leader Momonga waits alone in an underground graveyard for his teammates.
Momonga is perplexed after finding himself unable to log out from "Yggdrasil," and the humanlike actions of the NPCs are creeping him out.
Momonga finds a human village called Carne being attacked by a group of knights and decides to fight back.
Carne’s attackers are a special forces group from the Slane Theocracy. Their aim is to assassinate the warrior chief Gazef.
Momonga/Ainz’s next stop is the fortress citadel of E-Rantel. He changes his name to Momon and joins a guild of adventurers to improve his status.
Momon and the Swords of Darkness, a team of adventurers, head to Carne. The members are unable to disguise their surprise at Momon’s combat skills.
The team are surrounded by a group of armed goblins just before arriving at Carne, and find themselves saved by a young girl called Enri.
Momon returns safely to E-Rantel, having improved his status as an adventurer. Meanwhile a showdown with Clementine awaits Nfirea.
Khajiit continues the rites required to turn E-Rantel into a city of the dead. Momon challenges Clementine, who boasts of his great strength.
Momon/Ainz has ordered the vampire girl Shalltear to hunt humans with special abilities, but in the midst of his mission she loses control of herself.
Ainz is bewildered after being suddenly betrayed by Shalltear. The adventurers guild reports more sightings of vampires.
Ainz decides to battle with Shalltear alone and begins to prepare. Demiurge attempts to return to his master.
Ainz attempts to end Shalltear with instant kill magic, but it has no effect. He reveals everything to Shalltear, who is certain of her own victory.
After dealing with Shalltear, controlled by a mysterious enemy, Ainz decides to raise his guard and gather information about the new world.
After the threat of the messenger sent by Ainz, Zaryusu goes in search of help in the other villages of the lizardmen to prepare for war.
After bringing all five tribes together, it is now time for Zaryusu to face the undead army.
The army of the undead sent by Ainz has been defeated. How will the supreme lord react to the news?
The duel between Cocytus and the lizardmen will decide the fate of the village.
At Re-Estize, the eponymous capital of the kingdom, things start to move. Sebas saves a girl, unleashing the anger of the Eight Fingers.
The fields of black dust have been burned, but the capital is still in the hands of the Eight Fingers, while the Blue Roses prepare to fight them.
After informing members of the Blue Roses of the impending attack, Climb meets Sebas on the streets of the capital and asks him to train him.
Sebas, Brain and Climb launch an attack on the clandestine brothel, but waiting for them they find Succulent, a member of the Six Arms.
Ainz reaches the capital to test the loyalty of Sebas. Meanwhile, Princess Renner moves to win the marquis's support.
The operation begins to arrest the members of Eight Fingers, but in one of the buildings the adventurers run into some members of Nazarick.
Ainz finally confronts Jaldabaoth, forcing him to reveal his goal. And so the adventurers prepare for the decisive battle against the demons.
Humans face the demons that have invaded the capital. Evileye and Narberal accompany Ainz in the battle against the demon king, Jaldabaoth.
Nazarick is doing well, almost too well. Ainz tries to help his extremely loyal underlings work less by ordering them to relax, with varying results.
Ainz gathers a planning meeting but gets more than he'd bargained for. Meanwhile in Carne Village, Nfirea has his mind set on Enri's heart.
The threat in the Great Forest prompts an unlikely alliance between the Giant of the East and the Demon Snake of the West. Enri heads to E-Rantel.
Ainz reprimands Lupusregina for her failure to report. Later, he and Aura go on a recon mission to see who the Giant and Demon Snake really are.
The Giant's forces begin their attack on Carne Village. While protecting the villagers, Enri and Nfirea spot a troll climbing over the rear gate.
Momon visits the Baharuth Empire and accepts a job. Meanwhile, worker team Foresight takes on a mission to explore a tomb in the Re-Estize Kingdom.
Worker group Foresight arrives at Nazarick fearing the worst but finds low defenses and a large amount of treasure. But a surprise is waiting for them.
The members of Foresight suddenly find themselves in an arena facing Ainz and Albedo. They try to talk themselves out, but this sends Ainz into a rage.
At the Baharuth empire, Aura and Mare demand the emperor come forth and apologize. Seeing no other choice, Jircniv emerges and embarks for Nazarick.
The Baharuth Empire officially recognizes Nazarick as a country and its ally. Soon after, Gazef prepares for a fateful and costly battle.
Prince Barbro and the Royal Army arrive at Carne, taking Enri by surprise. As a tense situation quickly escalates, she resorts to desperate measures.
Despite a huge disadvantage, Ainz quickly turns the tide with a spell that annihilates his foes. Gazef orders a retreat, but it's too late.
Warrior Captain Gazef challenges Ainz to a one-on-one PVP duel in the face of almost certain death. Brain and Climb serve as witnesses to his bravery.
Unsure how to lead his kingdom, Sorcerer King Ainz goes over some proposals from the people of Nazarick with Albedo, who offers her blunt opinions.
Returning to the royal palace, Princess Renner tells a troubled Prince Zanac that a diplomatic delegation from the Sorcerer Kingdom will arrive soon.
Stressed about the threat of the Sorcerer Kingdom, Emperor Jircniv secretly plans to propose an alliance between his empire and the Slane Theocracy.
Intent on recruiting adventurers for his kingdom, Ainz visits the imperial capital and duels with an infamous gladiator known as the Warrior King.
Hoping to establish friendly relations and get his hands on rune technology, Ainz embarks on a journey to the kingdom of the dwarves.
With the Quagoa bearing down on a dwarven stronghold and the dwarves on the verge of abandoning it, Ainz arrives and offers to assist in its defense.
Wanting to even the odds against the surprisingly resilient dwarves, the Quagoa clan leader Riyuro asks a group of frost dragons for assistance.
While Zanac ponders the situation facing his realm, Philip comes up with a plan to force the Sorcerer Kingdom to lower its production of food crops.
The Sorceror Kingdom declares war on Re-Estize and gives it one month to prepare. Those aware of Ainz's power steel themselves for the coming fight.
After the movement of Ainz's forces becomes clear, Zanac decides to call his people to arms. Meanwhile, the Blue Roses receive a special request.
As Ainz's forces approach the royal city, the elite adventurer Azuth, clad in his crimson robotic suit, appears in the sky and attacks them.
During a meeting with Princess Renner, the Blue Roses suddenly turn on Lakyus and restrain her. Brain declares that he will challenge Ainz directly.
Refusing her father's request to flee the capital, Renner tasks Climb with hiding the royal treasures to prevent them from falling into Ainz's hands.